Telephone calling cards provide a convenient way for business and residential telephone subscribers to charge the costs of telecommunications services. This convenience can be attributed in part to a standardized calling card numbering plan administered by Bell Communication Research (Bellcore) which permits calling card calls to be billed to appropriate calling card subscribers regardless of the operator service and/or communications carrier used to complete these calls.
The Bellcore standards, set forth in Feature Specific Document OSSGR FSD85-01-0100 TR-NWT-001177, offer a card issuer three numbering plan options. In the first option, the card issuer provides the calling card subscriber with a Calling Card Number (CCN) comprised of a 10-digit Calling Card Account Number (CCAN) and a 4-digit Personal Identification Number (PIN). Typically, the 10-digit calling card account number, also called "line-based number", is the calling card subscriber's residential or business telephone number.
The second and third options of the Bellcore numbering plan provide for non-line-based card numbers. According to the second option, in particular, a card issuer can use as a calling card number a special billing number which also follows the format of a 10-digit number followed by a 4-digit PIN. However, in contradistinction to the line-based numbers, the first ten digits of the calling card number in the second option are different from the card subscriber's telephone number. Furthermore, the first four digits of the 10-digit number form a prefix called "Card Issuer Identification Number" (CIID) assigned by Bellcore to uniquely identify each card issuer.
The third option provides for non-line-based numbers referred to as Alternate Calling Card Numbers (ACCNs). These numbers follow an international numbering plan standardized by the Comite Consultatif International de Telephonie et de telegraphie (CCITT) and are comprised of a) a 2-digit major industry identifier code (e.g., the code "89" for the telecommunications industry b) a 1-to-3 digit world zone or country code (e.g., the code "1" for the North American Dialing Plan) c) a card issuer code (up to three digits), d) an individual account number (up to 12 digits) and an optional PIN (up to 16 digits). In North America, this option is sometimes called the 891 plan. The first 6 digits of the "891" plan form a prefix that uniquely identifies a card issuer. That prefix, like the CIID prefix of the second option, is used in the routing of calling card validation queries to the card issuer's validation database. The first three digits of the prefix can be omitted for domestic calls but are required for international calls. For line-based numbers, the area code is used to determine the specific RBOC that has issued the calling card.
Some card issuers, such as a number of Regional Bell Operating Companies (RBOCs) have implemented the first option of the Bellcore numbering plan primarily because line-based numbers are easily remembered by calling card users. However, because of this user-friendliness, line-based numbers are more readily used as a means for illegal access to telecommunications services, causing significant economic losses for calling card issuers and account reconciliation problems for calling card subscribers. In addition, when a calling card subscriber changes his or her telephone number, a change to his or her calling card number is also warranted. Additionally, card issuers that are also communications carriers, such as AT&T and the RBOCs have received complaints from their calling card customers expressing anger at the fact that calling card calls initiated from public telephones owned or operated by Alternative Operator Services (AOS) companies are billed to those calling card subscribers at a significantly higher rate than the tariff rates charged by those carriers for equivalent calling card calls handled by these carriers. Apparently, such calling card subscribers were of the belief, which is erroneous, that the use for a particular call of a calling card issued by a particular communications carrier necessarily means that the call will be handled by that carrier.
In response to these problems, some calling card issuers favor the use of non-line-based numbers, i.e., numbers based on the second or the third option of the Bellcore numbering plan. These options offer significant advantages over the first one. For example, a non-line-based number can be a "cradle to grave" number that does not need to be changed when the card subscriber gets a new telephone number. In addition, decoupling a card number from the card subscriber's telephone number decreases communication carriers' vulnerability to theft of communications services. Moreover, non-line-based numbers, unlike line-based numbers, offer no information from which a billing number can be inferred. Thus, when a non-line-based number is used, AOS companies have no choice but to prompt callers to enter a Carrier Access Code (CAC) so that the caller can be connected to a communications carrier which is capable of validating the card number. Hence, the latter carrier rather than the AOS company will ultimately route the call, which will then be billed at the tariff rate established by the carrier.
However, a major drawback associated with non-line-based numbers is that they are more difficult to remember than line-based numbers. This, moreover, makes it more likely that calling card users will engage in practices that defeat the intended security purposes of the card issuers. Thus, providing convenient access to telecommunication services for calling card users while enforcing user-transparent security measures is still a problem for card issuers and communication carriers alike.